Method for charging shot holes



May 28, 1957 J. P. DANN-1, sR

METHOD FOR CHARGING SHOT HOLES 3 Sheets-Sheet 1 Filed Feb. 19, 1955 m,wm m l A Mw. a D w D'. WQ J W. w w

May 28, 1957 J. P. DANIEL, SR

METHOD FOR CHARGING SHOT HOLES 3 Sheets-Sheet 2 Filed Feb. 19, 195s Fig.4

John P. Da.n/'e/, Sr.

JNVENTOR.

May 28, 1957 J. P. DANIEL.. sR

METHOD FOR CHARGING SHOT HOLES I5 She'ets-Sheet 3 Filed Feb. 19. 1953John P. Danie/,5r

INVENTOR.

BY ala/#wy Hmm United States Patent METHOD FOR CHARGING SHOT HOLES JohnP. Daniel, Sr., New Orleans, La.

Application February 19, 1953, Serial No. 337,835

Claims. (Cl. Z55-1.8)

This invention relates to a method and apparatus for constructing shotholes and particularly to an apparatus for drilling holes so that theshots may be placed therein and the drill cage removed before the shotis tired.

When making seismograph records it is customary to provide shot holes ofvariousdepths into the formation and to explode an explosive chargetherein so that the propagation of the shock waves through the earth maybe measured and recorded. This type of work is normally accomplished bytwo separate and independent crews. The first crew proceeds in `advanceof the second crew and the operation of the iirst crew comprises thedrilling of the necessary shot holes and the placing'of explosivecharges therein. The second crew follows behind the first crew andconnects up, tires the charges and records the shock waves. lnrelatively hard formations the process is substantially this simpleinasmuch as the shot holes may be readily drilled and the explosivecharges placed therein with no other steps to be accomplished by thetirst crew.

However, when making seismograph records in soft formations, such assand, swamp muck or other similar materials which will cave in, theoperation is much more complicated. Heretofore it has been necessary forthe first crew to drill the shot hole vand to leave the drill bit anddrill string in the finished shot hole. Then the explosive charge islowered into the interior of the drill string at the bottom thereof withthe drill string maintaining the walls of the `shot hole and preventingthe caving in of the surrounding formation while the charge is beingplaced. After the explosive charge has -been placed, the first crew thenmoves on in advance of the second crew who fires and records theexplosive charges and the shock waves effected thereby under normalcircumstances. After the explosive charges have been tired, it is thennecessary for either the lirst crew to return or a third crew to followthe second crew and retrieve those portions of the drill strings whichhave not been destroyed, the lower portions of the drill strings and thebits being broken off by the firing of the shots. In many instances thecost of salvaging the drill stringis substantially equal to or in excessof the value of the drill string reclaimed. However, in certain statesit is the law that the drill string must be removed. Since only one shotis fired in ea-ch shot hole, and since many such shot holes are formed,it will be readily apparent that seismographic operations in softformations are `very expensive. v

The present invention relates to a method and apparatus by which themajor portion of the toolvmay be salvaged for repeated use. y

This is accomplished according to the present invention by providing thedrill string with a cutter head having a knockout or frangible portionor a removable drill cutter head which may be removed so as to providean opening through which the charge may be placed while the detonatorcable or wire will be extended upwardly through the drill tubing. Afterthe charge has been pla-ced in the bottom of the hole the drill tubingmay be pulled up and taken away so that the entire tubing may be used inanother well thus salvaglng a major portion of the equipment. In orderto support the detonator wire in the tubing during the removal of thestring it is found that `a oat may 'be attached to the wire and theentire hole filled With water or other fluid so that the float willmaintain the wire in position inside of the tubing so that the tubingmay be raised over the float and even if the sides of the hole cave thedetonator wire will be in position for connection to any suitable firingequipment.

lt is accordingly an object of this invention to provide an improvedmethod of constructing shot holes.

it is lanother object of the invention to provide an improved tool fordrilling shot holes.

It is a further object of the invention to provide a drill head having aknockout portion therein.

lt is a further object of the invention to provide a drill head whichmay be detachably connected to the end of a drill stem.

Other objects and many of the attendant advantages of the presentinvention will be apparent from the following detailed description takenin conjunction with the accompanying drawing in which:

Figure 1 is a sectional elevation of a shot hole with the tool elevatedoff of the bottom in knockout position;

Figure 2 is Ia view similar to Figure l with the knockout removed andexplosive being lowered into position;

Figure 3 is a similar view with the hole ready to be shot;

Figure 4 is `an exploded perspective of one form ofA cutter hearlaccording to the invention;

Figure 5 is an elevation of a modified tool according to the invention;

Figure 6 is a view similar to Figure l but showing the modied tool;

Figure 7 is a view showing the placing of the charge with the modiliedtool; and y Figure 8 is a cross section of the tool taken substantiallyon the plane indicated by the line 8-8 of Figure 5.

In the exemplary embodiment according to Figure 1, the shot hole 10 isdrilled into loose or caving formation 12 by means of a drill head 14secured on the end of a hollow drill stem 16 which may be made of anydesired number of links or joints so that the shot hole 10 may be of anydesired depth.

In the modification according to Figures l to 4 inclusive, the drillhead 14 is provided with a threaded collar 20 which may be threadedlyengageable with the lower end of the tube 16 so that rotation of thetube 16 will rotate the head 14. A plurality of cutters 22 are providedon the head 14 and the head 14 is provided with an axial aperture 24such as the continuation of the bore of the tubing 16 so that drillfluid or other material may readily be forced down the tubing 16 and owoutwardly through the passage 24. A knockout plug 26 provided with asmall aperture 28 is mounted in the passage 24 to reduce the operatingsize thereof.

The knockout 26 is usually provided with a core member 30 which fitswithin the passage 24 and is provided with a ared skirt 32 for seatingagainst the shoulder 34 provided by the counterbore 36 so that the plug26 will be iirmly seated in the lowermost portion of the passage 24 andwill maintain the opening 28 so that the iluid in the tubing may beexpelled through the passage with,

. considerable velocity.

In order to maintain the knockout 26 in the passage 24 a frangible pin38 may be placed in a bore in the head 14 which communicates with labore 42 in the knockout 26.

In actuation or operation of the method with the tool according toFigures l to 4 the tool is operated so that the head 14 is driven intothe earth by a rotary motion to produce a hole 10 of any desired depth.When the desired depth -of hole has been reached the tool will be raisedupwardly a small distance from the bottom of the hole as shown in Figurel and the knockout weight 46 carried at the end f a cable 4S will belowered through the tubing 16 with sufficient force to strike theknockout 26 and break the frangible pin 38 so that the knockout 26 willbe removed from the passage 24 so that a relatively large a'xial openingwill be produced through the drill head 14. The tool will then be raiseda further distance from the bottom of the hole to provide a space 50below the bottom of `the tool so that an exalosive charge 52 may bereadily lowered through the aperture or passage 24 into the bottom ofthe hole.

In order to facilitate both the ring of the explosive charge 52 and thelowering thereof into the shot hole, a detonator wire or cable 54 isconnected to the explosive charge 52 prior to the lowering thereof inthe shot hole through the drill string or tubing 16. After the explosivecharge has been lowered into the bottom of the shot hole through thetubing 1.6, the upper end of the detonator wirel 54 is connected to afloat 56. The oat 56 is of a sufficiently small size so that it willpass through the passage 24 in the head 14 so that the entire drillstring including the head 14 may be removed over the float. After theexplosive charge 52 has been placed and the float 56 connected to thedetonator wire 54, the hole lo may be filled with fluid 58 throughsubstantially the surface of the ground lafter which the tubing 16 andthe head 14 are withdrawn from the shot hole 10. Once the explosivecharge 52 has been placed in the bottom of the hole 10, it is immaterialas to whether the walls of the hole 10 should cave in or otherwise bedistorted inasmuch as the oat 56 will maintain the upper end of thedetonator wire 54 readily accessible at the top of the hole 10. Thuswhen the second crew comes along, they may readily connect the upper endof the detonator wire 54 to a blasting machine 60.

In the modication according to Figures 5 to 8 inclusive, the tubing 62has the end portion thereof slidably engaged within a drill head 64having cutter points 66. The lower end of the tubing 62 is provided withdrive lugs `68 which engage with kerf slots 70' in the head 64. Thehead,64 is detachably maintained in position on the end of tubing 62 bymeans of a frangible pin 74. The pin 74 is received within apertures '76`and 78 of the head 64 and in apertures 80 yand 82 of the drill tube 62.ln the operation of this modification of the invention the stem 62 willbe lowered into the hole and rotated to rotate the drill head 64. Whenthe hole has been drilled to the desired depth the tool will be raisedto the point where the head` 64 is elevated above the bottom of the holeand the weight 46 on the line 48 will be lowered into the tubing 62where it will either encounter the frangible pin 74 and destroy it orhit the bottom of the head 64 so that the frangible pin 74 will besheared off and the head 64 will be depositedin the bottom of the hole.After which the tubing 62 will, be elevated sulciently above the head 74so that the explosive charge 52 may be readily placed between the bottomof the hole and the bottom of the tubing.

The explosive charge 52 is connected to the detonator Wire 54 in thesame manneras that described above and the explosive charge 52 is thenlowered through the tubing 62 into the bottom of the hole. The float 56is then attached to the upper end of the detonator wire 54 after whichthe hole is filled with water so that the float 56 will maintain thedetonator wire within reach from the surface at all times. After thefloat 56 has been placed in position, the tubing 62 will be removed andthe explosive charge 52 in the bottom of the hole will be available forring when the second -crew reaches the particular shot hole in question.

It will be apparent this invention provides a method by which theapparatus for constructing holes maybe readily recoveredv and used asoften as desired without inuencing the explosion within the hole. l'nfact, should the walls of the hole cave in about the explosive charge 52after the drill strings have been pulled, the shock waves resulting fromthe firing of the explosive charge 52 will be emitted under more nearlythose conditions which are actually desired,

It will be apparent from ,the foregoing disclosure of the method yofcharging shot holes that a great saving will result. In the first place,inasmuch as the major portion of the drilling tool including all of thedrill string will be removed from the shot hole immediately after theplacing of the charge, it is not necessary for the drilling crew tomaintain a very large supply of tubing as in the prior methods offorming shot holes in soft formations where it was necessary to leavelarge quantities of tubing in the shot holes prior to their tiring.Secondly, it will be apparent that the cost of preparing a shot holewill be reduced inasmuch as a majority of the drilling equipment will besalvaged. Thirdly, since the salvage operation is performed by the samecrew `as that which drills the shot holes and places the explosivecharge therein, it will be necessary for only `one set up by thedrilling crew so that the shot hole is both drilled and the drill stringis removed therefrom with the same equipment during the same setup.

For purpose of exemplication the presently preferred embodiment of theinvention has been shown and described according to the -best presentunderstanding thereof. It will be apparent to those skilled in the 'artthat changes and modifications may be made in the construction andarrangement of the parts thereof without departure from the true spiritand purpose of the invention.

What is claimed as new is as follows:

l. In the drilling of Shot holes with a drilling tool including a hollowdrill string having a bit secured thereto, the bit having a flow passagecommunicating with the drill string to provide for circulation ofdrilling fluid through the drill string and bit, the method of charginga shot hole while the drilling tool remains in the shot hole comprisinglifting the drilling tool `a slight distance above the bottom of theshot hole, removing a portion of the drilling tool to increasethecross-sectional area of the how passage to permit the passage of anexplosive charge through the drilling tool to a point therebelow,lowering an explosive charge 4into the drilling tool through the flowpassage and into the shot hole beneath the drilling tool, and thenwithdrawing the remainder of the drilling tool from the shot hole priorto detonating the explosive charge.

2. In the ydrilling of shot holes with a drilling tool including .ahollow drill string having a bit secured thereto, the bit having a flowpassage communicating with the drill string to provide for circulationof drilling fluid through vthe drill string and bit, the method ofcharging a shot hole while the drilling tool remains in the shot holecomprising lifting the drilling tool a slight distance above the bottomof the shot hole, removing a portion of the drilling tool to increasethe cross-sectional area of the flow passage to permit the passage of anexplosive charge through the drilling tool to a point therebelow,providing an explosive charge on one end of a detonator wire, loweringthe explosive charge and detonator wire into the drill string, throughthe ow passage and into the shot hole beneath the drill string whileretaining the other end of the detonator wire above the upper end of theshot hole, and then removing the drilling tool from the shot hole priorto detonating the explosive charge.

3. In the drilling of shot holes with Va drilling tool including ahollow drill string having a bit secured thereto, the bit having a owpassage communicating with the drill string to provide for circulationof. drilling fluid through the drill string and bit, the method ofcharging a shot hole while the drilling tool remains in the shot holecomprising lifting the drilling tool a slight distance above the bottomof the shot hole, removing a portion of the drilling tool to increasethe cross-sectional area of the ow passage to permit the passage of anexplosive charge through the drilling tool to a point therebelow,providing an explosive charge on one end of a detonator wire, loweringthe explosive charge and detonator wire into the drill string, throughthe ow passage and into the shot hole beneath the drill string whileretaining the other end of the detonator wire above the upper end of theshot hole, attaching a oat to the other end of the dentonator wire,placing liquid into the shot hole as is necessary to till the shot hole,removing the drilling tool and permitting the oat to be retained in anaccessible position on the surface of the liquid to facilitatedetonating the explosive charge.

4. In the drilling of shot holes with a drilling tool including a hollowdrill string having a bit secured thereto, said bit having an enlargedpassage therethrough, a plug positioned in the enlarged passage, saidplug having a reduced flow passage communicating with the drill stringto provide for circulation of drilling iluid through the drill stringand bit, the method of charging a shot hole while the drilling toolremains in the shot hole comprising lifting the drilling tool a slightdistance above the bottom of the shot hole, knocking out the plug topermit the passage of an explosive charge through the enlarged passageto a point below the bit, lowering an explosive charge into the drillingtool, through the enlarged passage and into the shot hole beneath thedrilling tool, and then withdrawing the drill string and bit from theshot hole prior to detonating the explosive charge.

5. In the drilling of shot holes with a drilling tool including a hollowdrill string having a bit releasably secured thereto, the method ofcharging a shot hole while the drilling ltool remains in the shot holecomprising lifting the drill string and bit a slight distance above thebottom of the shot hole, removing the bit from the drill string,lowering an explosive charge into the drill string and through the lowerend thereof into the shot hole beneath the drill string, and thenwithdrawing the drill string from the shot hole prior to detonating theexplosive charge.

References Cited in the tile of this patent UNITED STATES PATENTS185,447 LeConte Dec. 19, 1876 2,048,677 Berteling July 28, 19362,146,645 Newman Feb. 7, 1939 2,184,514 Cleesattel Dec. 26, 19392,300,813 Savage Nov. 3, 1942 2,614,804 Carlisle Oct. 21, 1952 2,621,895Toelke Dec. 16, 1952 2,665,886 Ellis Jan. 12, 1954 FOREIGN PATENTS296,352 Great Britain Aug. 28, 1928

